Using channel values in a Report text box

Hi,

I have a Report page with a graph that contains a text box in which I would like to enter a value from a channel. I am using the following text entry:

Roll Gradient = @@Str(ChD(ChnFind("InStr(1,Ch(""Metric Values/Metrics""),""Roll Grad [deg/'g']"",1)<>0"),"Metric Values/Values"), "dd.d")@@ deg/'g'

When the channels Metric Values/Metrics and Metric Values/Values exist then it works perfectly. However, if I open the Report file when those channels don't exist then several errors are thrown because, it seems, DIAdem is trying to evaluate the above text entry and failing to find the channels.

Is there a way of making this kind of text entry more robust so that errors are not thrown just because it can't be evaluated?

Ideally, script solutions should not be used, as I would like the end user to be able to open the Report file at times when those channels may not be present.

Thanks.

Simon.